U.S. patent number 7,450,719 [Application Number 10/759,719] was granted by the patent office on 2008-11-11 for gigabit ethernet-based passive optical network and data encryption method.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. Invention is credited to Jun-Sung An, Su-Hyung Kim, Young-Seok Kim, Hak-Phil Lee, Yun-Je Oh, Se-Kang Park, Tae-Sung Park, Whan-Jin Sung.
United States Patent |
7,450,719 |
Lee , et al. |
November 11, 2008 |
Gigabit Ethernet-based passive optical network and data encryption
method
Abstract
A Gigabit Ethernet-based passive optical network that can
reliably transmit data is disclosed. The network includes an OLT
for receiving a public key through a transmission medium,
encrypting a secret key by means of the received public key,
transmitting the encrypted secret key, encrypting data by means of
the secret key, and transmitting the encrypted data, the OLT being
located in a service provider-side. The network also includes an
ONT for transmitting the public key to the OLT, receiving the
secret key transmitted from the OLT, decrypting the secret key by
means of a private key, receiving the data, and decrypting the
received data by means of the decrypted the secret key. The public
key is used for encrypting the secret key. The secret key is
encrypted by means of the public key. The data is encrypted by the
OLT by means of the secret key.
Inventors: |
Lee; Hak-Phil (Inchon,
KR), Park; Se-Kang (Seonam-si, KR), Sung;
Whan-Jin (Suwon-si, KR), Kim; Young-Seok
(Seongnam-si, KR), Oh; Yun-Je (Yongin-si,
KR), An; Jun-Sung (Suwon-si, KR), Park;
Tae-Sung (Yongin-si, KR), Kim; Su-Hyung (Seoul,
KR) |
Assignee: |
Samsung Electronics Co., Ltd.
(Maetan-Dong, Yeongtong-Gu, Suwon-Si, Gyeonggi-Do,
KR)
|
Family
ID: |
34214688 |
Appl.
No.: |
10/759,719 |
Filed: |
January 16, 2004 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
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US 20050047602 A1 |
Mar 3, 2005 |
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Foreign Application Priority Data
|
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Aug 26, 2003 [KR] |
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10-2003-0059018 |
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Current U.S.
Class: |
380/256; 380/282;
380/30; 726/3; 726/2; 380/259 |
Current CPC
Class: |
H04L
9/0844 (20130101); H04L 9/0825 (20130101) |
Current International
Class: |
H04K
1/00 (20060101); H04L 9/00 (20060101); H04L
9/30 (20060101); G06F 17/30 (20060101); G06F
7/04 (20060101); G06K 9/00 (20060101); H04L
9/32 (20060101) |
Field of
Search: |
;380/256,30,259,282
;726/2,3 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Sheikh; Ayaz
Assistant Examiner: Chen; Shin-Hon
Attorney, Agent or Firm: Cha & Reiter, LLC
Claims
What is claimed is:
1. A Gigabit Ethernet-based passive optical network comprising: an
Optical Line Terminal (OLT) for receiving a public key through
transmission medium, encrypting a secret key by means of the
received public key, transmitting the encrypted secret key,
encrypting data by means of the secret key, and transmitting the
encrypted data, the OLT being located in a service provider-side;
and an Optical Network Terminal (ONT) for transmitting the public
key to the OLT, receiving the encrypted secret key transmitted from
the OLT, decrypting the encrypted secret key by means of a private
key residing in an ONT key management unit of the ONT for managing
a public key and the private key, receiving the encrypted data, and
decrypting the received encrypted data by means of the decrypted
secret key, wherein the public key is used for encrypting the
secret key, the secret key is encrypted by means of the public key,
and the data is encrypted by the OLT by means of the secret
key.
2. The Gigabit Ethernet-based passive optical network as claimed in
claim 1, wherein the OLT comprises: a GE-PON OLT MAC module for
transmitting input data to a predetermined path; a GMII module for
providing an interface between a transmission medium and the GE-PON
OLT MAC module; an OLT key management unit for managing a public
key transmitted from the ONT and a secret key for encrypting the
data; and a data encryption unit for encrypting the data by means
of the secret key.
3. The Gigabit Ethernet-based passive optical network as claimed in
claim 2, wherein the GMII module comprises: a PCS module for
selectively encoding or decoding input blocks of data and
outputting the encoded data or the decoded data; a PMA module for
selectively performing a serial conversion or a parallel conversion
with respect to input data and outputting the convened data; and a
PMD module for convening electrical signals, which are data output
from the PMA module, into optical signals, transmitting the optical
signals to the transmission medium, converting optical signals
received through the transmission medium 300 into electrical
signals, and transmitting the electrical signals to the PMA
module.
4. The Gigabit Ethernet-based passive optical network as claimed in
claim 2, wherein the OLT key management unit comprises: a public
key storage unit for storing a public key transmitted from the ONT;
a secret key generation unit for generating a secret key for
encrypting the data when the public key is stored in the public key
storage unit; and a secret key encryption unit for encrypting the
secret key generated by secret key generation unit by means of the
public key stored in the public key storage unit.
5. The Gigabit Ethernet-based passive optical network as claimed in
claim 1, wherein the ONT comprises: a GE-PON OLT MAC module for
transmitting input data to a predetermined path; a GMII module for
providing an interface between a transmission medium and the GE-PON
OLT MAC module; the ONT key management unit for decrypting the
encrypted data transmitted from the OLT by means of the private
key; and a data decryption unit for decrypting the encrypted data
transmitted from the OLT by means of the secret key decrypted by
the OLT key management unit.
6. The Gigabit Ethernet-based passive optical network as claimed in
claim 5, wherein the GMII module comprises: a PCS module for
selectively encoding or decoding input blocks of data and
outputting the encoded data or the decoded data; a PMA module for
selectively performing a serial conversion or a parallel conversion
with respect to input data and outputting the converted data; and a
PMD module for converting electrical signals, which are data output
from the PMA module, into optical signals, transmitting the optical
signals to the transmission medium, converting optical signals
received through the transmission medium 300 into electrical
signals, and transmitting the electrical signals to the PMA
module.
7. The Gigabit Ethernet-based passive optical network as claimed in
claim 1, wherein the ONT key management unit comprises: a public
key storage unit for storing the public key; a private key storage
unit for storing the private key; and a secret key decryption unit
for decrypting the encrypted secret key transmitted from the OLT by
means of the secret key stored in the private key storage unit, and
outputting the decrypted secret key to the data decryption
unit.
8. The Gigabit Ethernet-based passive optical network as claimed in
claim 1, wherein the public key and the private key are
respectively a RSA public key and a RSA private key.
9. The Gigabit Ethernet-based passive optical network as claimed in
claim 1, wherein the secret key is an AES secret key.
10. An encryption method for transferring data between an Optical
Line Terminal (OLT) and a plurality of Optical Network Terminals
(ONTs) in a Gigabit Ethernet-based passive optical network, the
encryption method comprising the steps of: a) transmitting, by the
ONT, a public key to the OLT; b) encrypting, by the OLT, a secret
key by means of the public key transmitted from the ONT and
transmitting the encrypted secret key to the ONT; c) decrypting, by
the ONT, the encrypted secret key transmitted from the OLT by means
of a private key residing in the ONT in an ONT key management unit
for managing a public key and the private key; d) encrypting, by
the OLT, data by means of the secret key and transmitting the
encrypted data to the ONT; and e) decrypting, by the ONT, the
encrypted data transmitted from the OLT by means of the decrypted
secret key.
11. The encryption method as claimed in claim 10, wherein step b)
comprises: b-1) storing the public key transmitted from the ONT;
b-2) generating a secret key for encrypting the data when the
public key is stored; b-3) encrypting the secret key by means of
the public key; and b-4) transmitting the encrypted secret key to
the ONT.
12. An encryption method for transferring data between an Optical
Line Terminal (OLT) and a plurality of Optical Network Terminals
(ONTs) in a Gigabit Ethernet-based passive optical network, the
encryption method comprising the steps of: a) transmitting, when
power is turned on and the OLT is driven, gate signals to the ONTs
in order to detect ONTs connected through a transmission medium; b)
transmitting, by the ONTs, registration requirement signals and RSA
public keys corresponding to the gate signal; c) registering, by
the OLT, the ONTs in accordance with the registration requirement
signals transmitted from the ONTs, assigning Logical Link IDs
(LLIDs) with respect to the ONTs, and transmitting information for
the assignment to the ONTs; d) encrypting, by the OLT, secret keys
by means of the public keys and transmitting the encrypted secret
keys to the ONTs; e) decrypting, by the ONTs, the encrypted secret
keys transmitted from the OLT by means of private keys residing in
an ONT key management unit ONT for managing a public key and a
private key; f) confirming, by the OLT and the ONTs, mutual sharing
of the public keys and the secret keys, the OLT assigning bandwidth
necessary for data transmission to the ONTs; g) encrypting, by the
OLT, data by means of the secret keys and transmitting the
encrypted data to the ONTs; and h) decrypting, by the ONTs, the
encrypted data transmitted from the OLT by means of the decrypted
secret keys.
13. An encryption method for transferring data by an Optical Line
Terminal (OLT) in a Gigabit Ethernet-based passive optical network,
the encryption method comprising the steps of: transmitting, when
power is turned on and the OLT is driven, gate signals through a
transmission medium; receiving registration requirement signals and
RSA public keys corresponding to the gate signals; registering the
received registration requirement signals, assigning respective
Logical Link IDs (LLIDs) with respect to the registration
requirement signals; transmitting information for the assignment;
encrypting secret keys by means of the public keys and transmitting
the encrypted secret keys; confirming mutual sharing of the public
keys and the secret keys; assigning bandwidths necessary for data
transmission; encrypting data using the secret keys; and
transmitting the encrypted data.
Description
CLAIM OF PRIORITY
This application claims priority to an application entitled
"Gigabit Ethernet-based passive optical network which can reliably
transmit data and data encryption method using the same," filed in
the Korean Intellectual Property Office on Aug. 26, 2003 and
assigned Serial No. 2003-59018, the contents of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a gigabit Ethernet-based passive
optical network including an optical line terminal (OLT) provided
in a service provider-side and a plurality of optical network
terminals (ONT) provided in a user-side, and more particularly to
an encryption method for data security between the OLT and the
plurality of ONTs.
2. Description of the Related Art
Currently, large quantities of data can be shared in an online
state owing to expansion of public networks such as various
wireless networks and an ultra-high speed communication network.
Data sharing in an offline state is widely used through high
capacity storage media such as CDs and DVDs. In this way, users can
receive numerous types of data shared online and offline. However,
security systems for such online and offline data sharing systems
are generally weak.
A passive optical network (hereinafter, referred to as a PON) is a
communication network system that transmits signals to an end-user
through an optical cable network. The PON includes one OLT
installed on a communication company and a plurality of ONTs
installed in a subscriber's premise. In general, a maximum of 32
ONTs can be connected to one OLT.
The PON can provide each UE (user) with 622 Mbps of bandwidth in
downstream transmission and 155 Mbps of bandwidth in upstream
transmission, which can be assigned to a plurality of users
utilizing the PON. The PON can be used as a trunk between a large
scale system such as a cable TV system and a nearby building, or
between a large scale system and an Ethernet network for a
household using a coax cable.
The OLT transmits a corresponding signal to the ONT through an
optical cable. The ONT receives the signal transmitted from the
OLT, processes the received signal, and then transmits the
processed signal to an end-user. The ONT, which is a transport
system in a service subscriber-side, constitutes terminating
equipment in an optical communication network that provides a
service interface to an end-user.
The ONT services a fiber to the curb (FTTC), a fiber to the
building (FTTB), a fiber to the floor (FTTF), a fiber to the home
(FTTH) and a fiber to the office (FTTO), etc. Therefore, the ONT is
required to provide high service accessibility for users. The ONT
connects a cable, which is connected to a subscriber and which
transmits an analog signal transmitted from the subscriber, to
optical facilities that are connected to the OLT and transceive
optical signals.
In this way, the ONT converts an optical signal transmitted from
the OLT into an electric signal (photoelectric conversion), and
transmits the converted signal to a subscriber. In addition, the
ONT converts an electric signal transmitted from a subscriber into
an optical signal (electrooptic conversion), and transmits the
converted signal to the OLT.
FIG. 1 is a block diagram showing a downstream transmission
structure of data in a Gigabit Ethernet-PON, and FIG. 2 is a block
diagram showing an upstream transmission structure of data in the
Gigabit Ethernet-PON.
As shown in FIGS. 1 and 2, the Gigabit Ethernet-PON (hereinafter,
referred to as a GE-PON) has a tree structure in which one OLT 10
is connected to a plurality of ONTs 20, 22 and 24 through an
optical coupler 15. Using the GE-PON, a cost-effective subscriber
network can be constructed as compared to an activity-on-node
(AON).
The first type of GE-PON standardized was an asynchronous transfer
mode passive optical network (hereinafter, referred to as an
ATM-PON). ATM cells are transmitted upstream or downstream in the
form of blocks each of which consists of a predetermined number of
ATM cells. In contrast, in an Ethernet-PON (hereinafter, referred
to as an E-PON), packets having different sizes are transmitted in
the form of blocks, each of which includes a predetermined number
of packets. Accordingly, the E-PON has a more complex control
structure in contrast to the ATM-PON.
The downstream transmission of data will be described with
reference to FIG. 1. In the case of the downstream transmission,
the OLT 10 broadcasts data to be transmitted to the ONTs 20, 22 and
24. When the data transmitted from the OLT 10 is received, the
optical coupler 15 transmits the received data to each of the ONTs
20, 22 and 24. Each of the ONTs 20, 22 and 24 detects data that is
to be transmitted to each of users 30, 32 and 34 from the data
transmitted from the optical coupler 15. Then, each of the ONTs 20,
22 and 24 transmits only detected data to each of users 30, 32 and
34.
The upstream transmission of data will be described with reference
to FIG. 2. In the case of the upstream transmission, data
transmitted from each of the users 30, 32 and 34 is transmitted to
each of the ONTs 20, 22 and 24. Each of the ONTs 20, 22 and 24
transmits the data transmitted from the users 30, 32 and 34 to the
optical coupler 15 when transmission permission is promised by the
OLT 10. In this case, each of the ONTs 20, 22 and 24 transmit
upstream each data received during time set by a time division
multiplexing (TDM) method. Accordingly, data collision according to
upstream transmission of data does not occur in the optical coupler
15.
With the development of Internet technology, service subscribers
have required data services which need larger bandwidths and have
been attracted to an end-to-end transmission using Gigabit Ethernet
technology which is relatively low-priced and can secure a higher
bandwidth in comparison to the ATM technology which requires
relatively expensive equipment, has limitation in the bandwidth,
and must perform segmentation of IP packets. Thus, even in a PON
structure of a subscriber network, the Ethernet type is required
rather than the ATM.
In a packet protocol data unit (hereinafter, referred to as PDU),
an encryption method used in the ATM-PON. An encryption key having
a size of 24 bytes is used as a churning key. Since the method has
encryption ability that enables a value of a key to be updated each
second and uses a relatively simple algorithm, it is used so that
high-speed support may be performed in an ATM-PON having a speed of
622 Mbps. Periodically updated values of a key are generated in an
ONT, inserted into a payload portion in an operation,
administration and maintenance (hereinafter, referred to as an OAM)
cell, and then transmitted to each OLT.
The packet PDU encryption method includes data over cable service
interface specification (DOCSIS) method using a data encryption
standard with cipher block chaining (DES-CBC) encryption method in
addition to the churning method.
In the case of the ATM-PON, a churning key of 3 bytes is inserted
into the OAM cell owing to both limitation of encryption technology
and possibility of high-speed support, but it causes a limitation
in the ability of the encryption key itself.
Since the GE has a faster speed than the ATM-PON (e.g., 622 Mbps),
it is inefficient for the GE to use the encryption method of the
ATM-PON. Key period in the DOCSIS using the DES-CBC encryption
method must be repeated every 12 hours so that authorized
wiretapping by malicious users can be prevented.
Accordingly, when the DES-CBC encryption method is applied to the
GE-PON, the application may aggravate inefficiency to an OLT, which
must manage a plurality of ONTs in a point-to-multipoint structure.
Further, since the GE-PON has a point-to-multipoint structure,
which is relatively vulnerable to encryption, the encryption
problem of user data transmitted through an upstream/downstream
link is significant. Accordingly, a powerful and efficient
encryption key method must be selected and effectively used.
However, standardization with respect to an encryption method of
the GE-PON and key management scheduling scheme is just being
developed in IEEE 802.3ah, and it is in a state in which a packet
format has not been decided yet.
SUMMARY OF THE INVENTION
One aspect of the present invention is related to a Gigabit
Ethernet-based passive optical network that can reliably transceive
data between one OLT and a plurality of ONTs and a data encryption
method using the same.
Another aspect of the present invention is related to a Gigabit
Ethernet-based passive optical network that can heighten security
with respect to data when a downstream transmission is performed
from one OLT to a plurality of ONTs and a data encryption method
using the same.
Yet another embodiment of the present is directed to a Gigabit
Ethernet-based passive optical network including an OLT for
receiving a public key through a transmission medium, encrypting a
secret key by means of the received public key, transmitting the
encrypted secret key, encrypting data by means of the secret key,
and transmitting the encrypted data. The OLT is located in a
service provider-side The network also includes an ONT for
transmitting the public key to the OLT, receiving the secret key
transmitted from the OLT, decrypting the secret key by means of a
private key, receiving the data, and decrypting the received data
by means of the decrypted the secret key. The public key is used
for encrypting the secret key. The secret key is encrypted by means
of the public key. The data is encrypted by the OLT by means of the
secret key.
In another embodiment, the OLT includes a GE-PON OLT MAC module, a
GMII module, an OLT key management unit, and a data encryption
unit. The GE-PON OLT MAC module transmits input data to a
predetermined path. The GMII module provides an interface between a
transmission medium and the GE-PON OLT MAC module. The OLT key
management unit manages a public key transmitted from the ONT and a
secret key for encrypting the data. The data encryption unit
encrypts the data by means of the secret key.
In another embodiment, the GMII module includes a PCS module, a PMA
module, and a PMD module. The PCS module selectively encodes or
decodes input data by the unit of a predetermined block and
outputting the encoded data or the decoded data. The PMA module
selectively performs a serial conversion or a parallel conversion
with respect to inputted data and outputting the converted data.
The PMD module converts electrical signals, which are data output
from the PMA module, into optical signals, transmits the optical
signals to the transmission medium, converts optical signals
received through the transmission medium 300 into electrical
signals, and transmits the electrical signals to the PMA
module.
The OLT key management unit may include a public key storage unit,
a secret key generation unit, and a secret key encryption unit. The
public key storage unit stores a public key transmitted from the
ONT. The secret key generation unit generates a secret key for
encrypting the data when the public key is stored in the public key
storage unit. The secret key encryption unit encrypts the secret
key generated by secret key generation unit by means of the public
key stored in the public key storage unit.
The ONT may include a GE-PON OLT MAC module, a GMII module, an ONT
key management unit, and a data decryption unit. The GE-PON OLT MAC
module transmits input data to a predetermined path. The GMII
module provides an interface between a transmission medium and the
GE-PON OLT MAC module. The ONT key management unit manages a public
key and a private key and decrypts the encrypted data transmitted
from the OLT by means of the private key. The data decryption unit
decrypts the encrypted data transmitted from the OLT by means of
the secret key decrypted by the OLT key management unit. The GMII
module may have the same structure as that of the GMII module
included in the OLT.
The ONT key management unit may include a public key storage unit
for storing the public key, a private key storage unit for storing
the private key; and a secret key decryption unit for decrypting
the encrypted secret key transmitted from the OLT by means of the
secret key stored in the private key storage unit, and outputting
the decrypted secret key to the data decryption unit.
In one aspect of the present invention, the public key and the
private key respectively represent a RSA public key and a RSA
private key. The secret key may be an AES secret key.
Yet another embodiment of the present invention is directed to an
encryption method including the steps of: a) the ONT transmitting a
public key to the OLT; b) the OLT encrypting a secret key by means
of the public key transmitted from the ONT and transmitting the
encrypted secret key to the ONT; c) the ONT decrypting the
encrypted secret key transmitted from the OLT by means of a private
key; d) the OLT encrypting data by means of the secret key and
transmitting the encrypted data to the ONT; and e) the ONT
decrypting the encrypted data transmitted from the OLT by means of
the decrypted secret key.
For example, the OLT may encrypt the AES secret key by means of the
RSA public key transmitted from the ONT and transmits the encrypted
AES secret key to the ONT. The OLT encrypts data by means of the
AES secret key and transmits the encrypted data to the ONT.
Accordingly, data can be efficiently encrypted in the GE-PON having
a point-to-multipoint structure.
In addition, the ONT may transmit the RSA public key to the OLT,
and the public key is shared by the ONT and the OLT. The OLT
encrypts the AES secret key, which is used for encrypting data be
means of the RSA public key, and transmits the encrypted AES secret
key to the ONT, and the secret key is shared by the ONT and the
OLT. Accordingly, data, which will be transmitted, can be
efficiently encrypted in a GE-PON having the point-to-multipoint
structure.
In such a GE-PON, the OLT and a plurality of ONTs share the RSA
public key and the AES secret key in a state in which they mutually
correspond in a one-to-one fashion. Further, only the ONT having a
corresponding AES secret key capable of decrypting encrypted data
can decrypt data by means of corresponding AES secret key, even
through the OLT encrypts data by means of corresponding AES secret
key and transmits the encrypted data to all the ONTs. Accordingly,
data can be efficiently encrypted in a network structure having a
point-to-multipoint structure.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will be more apparent from the following detailed
description taken in conjunction with the accompanying drawings, in
which:
FIG. 1 is a block diagram showing a downstream transmission
structure of data in a Gigabit Ethernet passive optical
network;
FIG. 2 is a block diagram showing an upstream transmission
structure of data in a Gigabit Ethernet passive optical
network;
FIG. 3 is a block diagram of a Gigabit Ethernet passive optical
network that encrypts data in order to reliably transceive data
between an OLT and an ONT according to an embodiment of the present
invention;
FIG. 4 is a detailed block diagram of the OLT key management unit
and the ONT key management unit in FIG. 3;
FIG. 5 is a flowchart illustrating a first embodiment of a data
encryption method which can reliably transmit data between one OLT
and a plurality of ONTs in a Gigabit Ethernet passive optical
network structure according to aspects of the present invention;
and
FIG. 6 is a flowchart illustrating a second embodiment of a data
encryption method which can reliably transmit data between one OLT
and a plurality of ONTs in a Gigabit Ethernet passive optical
network structure according to aspects of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, various embodiments of the present invention will be
described with reference to the accompanying drawings. The same
reference numerals are used to designate the same elements as those
shown in other drawings. In the below description, many particular
items, such as detailed elements of circuit, are shown, but these
are provided for helping the general understanding of the present
invention, it will be understood by those skilled in the art that
the present invention can be embodied without particular items. In
the following description of the present invention, a detailed
description of known functions and configuration incorporated
herein will be omitted when it may obscure the subject matter of
the present invention.
Hereinafter, a data encryption method for reliably transfer data
between one OLT and a plurality of ONTs in a Gigabit Ethernet
passive optical network (hereinafter, referred to as a GE-PON)
structure according to one embodiment the present invention will be
in detail described. The data encryption method utilizes an
advanced encryption standard (hereinafter, referred to as an AES)
secret key algorithm that uses a secret key having a length of 128
bits or a Rijndael algorithm. A rivest, shamir and adleman (RSA)
public key algorithm using a public key and a private key which
have a length of 1024 bits is utilized as a key encryption
algorithm for exchanging the secret key between an OLT and an ONT
on an open line.
A detailed description with respect to the AES secret key algorithm
and the RSA public key algorithm is disclosed in both the reference
R. Rivest, A. Shamir, and L. Adleman, "A Method for Obtaining
Digital Signatures and Public-key Cryptosystems," Communications of
the ACM, 21 (2), pp, 120-126, February 1978 and the reference RSA
Laboratories, "PKCS #1 v2.1: RSA Cryptography Standard," June
2002.
As described above, the standard regarding an initial registration
procedure between an OLT and an ONT in a GE-PON has been already
published, but no item regarding data encryption for transferring
data has been decided yet. Accordingly, in various embodiments of
the present invention, entire data, except for a destination
address (DA) field and a source address (SA) field in a standard
packet format of the GE-PON, are encrypted in the course of data
encryption using the AES secret key algorithm in the GE-PON.
The AES secret key is encrypted with the RSA public key by means of
the RSA algorithm. The encrypted AES secret key is inserted into a
user data protocol data unit (PDU) portion in an Ethernet frame and
then transmitted to a lower layer.
In another embodiment of the present invention, no data can be
transmitted as plaintext before a secret key and a public key are
completely exchanged between the OLT and the ONT. Therefore,
transmission between an OLT and an ONT must obey a standard GE-PON
registration procedure that includes a key exchange procedure for
data encryption.
FIG. 3 is a block diagram of a GE-PON that encrypts data in order
to reliably transfer data between an OLT and an ONT according to an
embodiment of the present invention. For reference, data encryption
may be performed in a data link layer or a GE-PON MAC layer
corresponding to an open systems interconnection (hereinafter,
referred to as an OSI) layer 2.
As shown in FIG. 3, the GE-PON includes an OLT 100 and an ONT 400
that set mutual channels and transfers data through a transmission
medium 300.
The OLT 100 may include a GE-PON OLT MAC module 120, a Gigabit
media independent interface (hereinafter, referred to as a GMII)
module 130, an OLT key management unit 200 and a data encryption
unit 180.
The GE-PON OLT MAC module 120 supports a CSMA/CD operation with
respect to data input from the OSI layer 2 from among OSI layer 7.
The GMII module 130 provides a mutual interface between a physical
layer, which is an OSI layer 1, and a MAC layer which is an OSI
layer 2. The GMII is an interface that expands a media independent
interface (hereinafter, referred to as MII) used in a high-speed
Ethernet, which supports data processing speeds of 10 Mbps, 100
Mbps and 1000 Mbps. Since the GMII module 130 has a data
transceiving path of 8 independent bits, it can support full-duplex
and half-duplex transmission.
The GMII in which the GMII module 130 is located includes three
sub-layers. The GMII includes a physical coding sub-layer
(hereinafter, referred to as PCS), a physical medium attachment
(hereinafter, referred to as PMA), and a physical medium dependent
(hereinafter, referred to as PMD). Each of the sub-layer includes a
module corresponding to each sub-layer.
A PCS module 140 provided in the PCS encodes and decodes input data
by the unit of a predetermined block. A PMA module 160 provided in
the PMA sub-layer performs a serial conversion with respect to data
input from the PCS through the PCS module 140, and it performs a
parallel conversion with respect to data input from the PMD
sub-layer. A PMD module 170 provided in the PMD sub-layer converts
an electrical signal, which is data transmitted from the PMA
sub-layer through the PMA module 160, into an optical signal, and
then transmits the optical signal to the transmission medium 300.
The PMD module 170 converts an optical signal received through the
transmission medium 300 into an electrical signal and then
transmits the electrical signal to the PMA sub-layer.
When a RSA public key transmitted from the ONT 400 is received, the
OLT key management unit 200 generates an AES secret key and
encrypts the AES secret key by means of the RSA public key. The AES
secret key encrypted as described above is transmitted to the ONT
400 through the transmission medium 300 via the GE-PON OLT MAC
module 120 and the GMII module 130.
The data encryption unit 180 encrypts plaintext data by means of
the AES secret key. Cryptography data encrypted as described above
is transmitted to the ONT 400 through the transmission medium 300
via the GE-PON OLT MAC module 120 and the GMII module 130.
The ONT 400 may also include a GE-PON OLT MAC module 420 and a GMII
module 430, an ONT key management unit 500 and a data decryption
unit 480.
The GE-PON OLT MAC module 420 and the GMII module 430 respectively
correspond to the GE-PON OLT MAC module 120 and the GMII module 130
and perform the same functions as those of the GE-PON OLT MAC
module 120 and the GMII module 130. The ONT key management unit 500
includes the RSA public key, which is used for encrypting the AES
secret key in the OLT 100, and a RSA private key used for
decrypting the AES secret key encrypted by means of the RSA public
key.
When the ONT 400 needs to receive a data service from the OLT 100,
the ONT key management unit 500 transmits a stored RSA public key
to the OLT 100 through the transmission medium 300 via the GE-PON
OLT MAC module 420 and the GMII module 430. When an AES secret key,
which has been encrypted by means of the RSA public key transmitted
to the OLT 100, is received, the ONT key management unit 500
decrypts the encrypted AES secret key by means of a stored RSA
private key.
When data encrypted by means of the AES secret key are received
from the OLT 100, the data decryption unit 480 decrypts the
encrypted data by means of the AES secret key decrypted by the ONT
key management unit 500.
As described above, the OLT 100 encrypts the AES secret key by
means of the RSA public key transmitted from the ONT 400 and
transmits the encrypted AES secret key to the ONT 400. The OLT 100
encrypts data by means of the AES secret key and transmits the
encrypted data to the ONT 400. In this way, data can be efficiently
encrypted in the GE-PON having a point-to-multipoint structure.
The ONT 400 transmits the RSA public key to the OLT 100, and the
public key is shared by the ONT 400 and the OLT 100. The OLT 100
encrypts the AES secret key, which is used for encrypting data by
means of the RSA public key, and transmits the encrypted AES secret
key to the ONT 400, and thus the secret key is shared by the ONT
400 and the OLT 100. In this way, data, which will be transmitted,
can be efficiently encrypted in a GE-PON having the
point-to-multipoint structure.
FIG. 4 is a detailed block diagram of the OLT key management unit
200 and the ONT key management unit 500 in FIG. 3.
The OLT key management unit 200 includes a public key storage unit
220, a secret key encryption unit 240 and a secret key generation
unit 260. The public key storage unit 220 stores a RSA public key
transmitted from the ONT 400. The secret key encryption unit 240
encrypts an AES secret key by means of the RSA public key stored in
the public key storage unit 220. When the RSA public key is
received by the OLT 100, the secret key generation unit 260
generates the AES secret key and provides the generated AES secret
key to the secret key encryption unit 240. Then, the secret key
encryption unit 240 encrypts the AES secret key generated by the
secret key generation unit 260 by means of the RSA public key
stored in the public key storage unit 220, and transmits the
encrypted AES secret key to the GE-PON OLT MAC module 120.
The data encryption unit 180 encrypts input data by means of the
AES secret key generated by the secret key generation unit 260 and
transmits the encrypted data to the GE-PON OLT MAC module 120.
The ONT key management unit 500 includes a public key storage unit
520, a private key storage unit 540 and a secret key decryption
unit 560.
The public key storage unit 520 stores the RSA public key used for
encrypting the AES secret key in the OLT 100. When the ONT 400
needs to receive a data service from the OLT 100, the ONT key
management unit 500 transmits the RSA public key stored in the
public key storage unit 520 to the GE-PON OLT MAC module 420. The
private key storage unit 540 stores the RSA private key used for
decrypting the AES secret key encrypted by means of the RSA public
key transmitted from the OLT 100. When the encrypted AES secret key
is received from the OLT 100, the secret key decryption unit 560
decrypts the encrypted AES secret key by means of the RSA private
key stored in the private key storage unit 540.
When the encrypted data is received from the OLT 100, the data
decryption unit 480 decrypts the encrypted data using the means of
the AES secret key decrypted by the secret key decryption unit
560.
In this way, the OLT 100 and the ONT 400 mutually share the RSA
public key and the AES secret key, and the OLT 100 encrypts data by
means of the AES secret key and then transmits the encrypted AES
secret key to the ONT 400, thereby enabling secure data
transmission to be performed.
FIG. 5 is a flowchart illustrating a first embodiment of a data
encryption method that can reliably transmit data between an OLT
and a plurality of ONTs in a GE-PON structure.
First, when the ONT 400 needs to receive a service from the OLT
100, the ONT 400 transmits a signal, which requires a registration,
and the RSA public key, which is stored in the public key storage
unit 520, to the OLT 100 in step S100. When the registration
requirement signal transmitted from the ONT 400 is received, the
OLT 100 registers and stores the received RSA public key in the
public key storage unit 220 in step S110.
When the RSA public key is registered and stored in the public key
storage unit 220, the secret key generation unit 260 generates an
AES secret key and provides the generated AES secret key to the
secret key encryption unit 240 in step S120. In step S130, the
secret key encryption unit 240 encrypts the AES secret key, which
is provided by the secret key generation unit 260, by means of the
RSA public key stored in the public key storage unit 220. In step
S140, the OLT 100 transmits the AES secret key encrypted by the
secret key encryption unit 240 to the ONT 400.
In step S150, the secret key decryption unit 560 in the ONT 400
decrypts the encrypted AES secret key transmitted from the OLT 100
by means of the RSA private key stored in the private key storage
unit 540 and stores the decrypted AES secret key. When the
decryption with respect to the AES secret key is completed, the ONT
400 transmits decryption completion information to the OLT 100 in
step S160. When the OLT 100 receives the decryption completion
information, the OLT 100 encrypts corresponding data by means of
the AES secret key generated by the secret key generation unit 260,
transmits the encrypted data to the ONT 400, and then the ONT 400
performs data transmission corresponding to the transmission in
step S170.
In this way, the OLT 100 and the ONT 400 mutually share the RSA
public key and the AES secret key, and the OLT 100 encrypts data by
means of the AES secret key and then transmits the encrypted AES
secret key to the ONT 400, thereby efficiently encrypting data in
the GE-PON having a point-to-multipoint structure.
FIG. 6 is a flowchart illustrating a second embodiment of a data
encryption method that can reliably transmit data between an OLT
and a plurality of ONTs in a GE-PON structure. In this embodiment,
the data encryption method is applied in an initial registration
step between the OLT 100 and the ONT 400. In FIG. 6, an ONT 1 400a
and an ONT 2 400b have the same inside construction as that of the
ONT 400 shown in FIG. 3 and FIG. 4.
The data encryption method includes an initial search step S200, a
public key transmission and a logical link ID (hereinafter,
referred to as a LLID) assignment step S300, a secret key
transmission and a time assignment step S400, a key sharing state
confirmation and bandwidth assignment step S500, and a
communication performance step S600. Hereinafter, the data
encryption method will be described.
When power is turned on and the OLT 100 is driven, the OLT 100
transmits gate signals to each of the ONTs in order to detect ONTs
connected through a communication medium in step S220a and S220b.
The ONT 1 400a and the ONT 2 400b from among a plurality of ONTs
will be employed and described.
The OLT 100 transmits the gate signals to the ONT 1 400a and the
ONT 2 400b at predetermined time intervals until registration
requirement signals are received, in step S320a and S320b. When the
gate signals transmitted from the OLT 100 are received, the ONT 1
400a and the ONT 2 400b transmit a registration requirement signal
and each RSA public key stored in each public key storage unit to
the OLT 100, in response to each gate signal, in step S340 and
S350.
When the registration requirement signals and the RSA public keys
transmitted from the ONT 1 400a and the ONT 2 400b are received,
the OLT 100 registers the ONT 1 400a and the ONT 2 400b,
registers/stores each RSA public key in the public key storage unit
220, and assigns LLIDs with respect to the ONT 1 400a and the ONT 2
400b. The OLT 100 transmits registration information and LLID
assignment information of the ONT 1 400a and the ONT 2 400b so as
to correspond to the ONT 1 400a and the ONT 2 400b, in step S360
and S370.
The OLT 100 generates and encrypts AES secret keys by means of each
RSA public key transmitted from the ONT 1 400a and the ONT 2 400b.
It takes a predetermined amount of time to perform such processes.
Accordingly, while such processes are performed, the OLT 100
transmits information (encryption progress information: Null),
which represents that the AES secret keys are being encrypted by
means of the RSA public keys, to the ONT 1 400a and the ONT 2 400b
in step S420 and S430. The ONT 1 400a and the ONT 2 400b receive
the encryption progress information and transmit response
information (Null response information) with respect to the
encryption progress information to the OLT 100 in step S440 and
S450.
When the AES secret keys are completely encrypted by means of the
RSA public keys during such processes, the OLT 100 transmits the
encrypted AES secret keys to corresponding ONT 1 400a and ONT 2
400b in step S460 and S470. The ONT 1 400a and the ONT 2 400b
receive the encrypted AES secret keys from the OLT 100, decrypt the
encrypted AES secret keys by means of RSA private keys and transmit
decryption and response information with respect to the decryption
to the OLT 100 in step S480 and S490.
When the decryption and response information are received from the
ONT 1 400a and the ONT 2 400b, the OLT 100 transmits transmission
permission information to the ONT 1 400a and the ONT 2 400b in step
S520 and S530. The transmission permission information includes
bandwidth assignment information with respect to the ONT 1 400a and
the ONT 2 400b and sharing state information with respect to the
RSA public keys and the AES secret keys. The ONT 1 400a and the ONT
2 400b receive the transmission permission information and transmit
response information with respect to the transmission permission
information to the OLT 100 in step S540 and S550.
The OLT 100, the ONT 1 400a and the ONT 2 400b, which mutually
share the RSA public key and the AES secret key through the
aforementioned processes, mutually transmit data encrypted by means
of the AES secret key in step S560 and S570.
As described above, in the GE-PON, the OLT 100 and a plurality of
ONTs share the RSA public key and the AES secret key in a state in
which they mutually correspond in a one-to-one fashion. Only an ONT
having a corresponding AES secret key capable of decrypting
encrypted data can decrypt data by means of corresponding AES
secret key, even through the OLT 100 encrypts data by means of
corresponding AES secret key and transmits the encrypted data to
the ONTs. In this way, data can be efficiently encrypted in a
network structure having a point-to-multipoint structure.
In accordance with aspects of the present invention, the OLT
encrypts the AES secret key by means of the RSA public key
transmitted from the ONT and transmits the encrypted AES secret key
to the ONT. Further, the OLT encrypts data by means of the AES
secret key and transmits the encrypted data to the ONT. In this
way, data can be efficiently encrypted in the GE-PON having a
point-to-multipoint. The ONT transmits the RSA public key to the
OLT, and the public key is shared by the ONT and the OLT. The OLT
encrypts the AES secret key, which is used for encrypting data be
means of the RSA public key, and transmits the encrypted AES secret
key to the ONT, and the secret key is shared by the ONT and the
OLT. In this way, data, which will be transmitted, can be
efficiently encrypted in a GE-PON having the point-to-multipoint
structure.
In such a GE-PON, the OLT and a plurality of ONTs share the RSA
public key and the AES secret key in a state in which they mutually
correspond in a one-to-one fashion. Only ONTs having a
corresponding AES secret key capable of decrypting encrypted data
can decrypt data by means of corresponding AES secret key, even
through the OLT encrypts data by means of corresponding AES secret
key and transmits the encrypted data to the ONTs. In this way, data
can be efficiently encrypted in a network structure having a
point-to-multipoint structure.
While the invention has been shown and described with reference to
certain preferred embodiments thereof, it will be understood by
those skilled in the art that various changes in form and details
may be made therein without departing from the spirit and scope of
the invention as defined by the appended claims.
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